By contrast, the pearls sometimes labeled as “Chinese akoyas”, “baby akoyas”, or “freshwater akoyas (AK)” are freshwater ...

Diamonds are the most amazing of gems. Just as amazing, however, is how natural diamonds reach Earth’s surface. Diamonds are formed 150 to 700 km deep in Earth, and are then carried upward in a rare ...

Figure 1. This demantoid was faceted to better reveal the “horsetail” inclusions. The sample is 8 mm in diameter. Photo by U. Hennebois. The exact origin and composition of the “horsetail” inclusions ...

If you're attending AGTA in person, take the quiz corresponding to the day you're visiting. Each daily quiz is based on the specific minerals displayed at the GIA booth that day, giving attendees a ...

GIA Student Workrooms give you affordable access to all the equipment and gemstones you need to complete the practical requirements of your Gem Identification course through Online Education. This ...

Diamonds have a long history as a premier gemstone—a natural consequence of their beauty, rarity, and superlative physical properties such as extreme hardness. Diamonds that are mined for use as ...

Descending into Peshawar for the first time, a foreign tourist might be surprised to learn that amid the clutter of buildings in this historical city lies an important gem trading center. This market ...

The Karowe Diamond Mine in Botswana, owned and operated by Lucara Diamond Corp., has gained international recognition for producing large, high-quality type IaB or coexistence of IaB with IIa diamonds ...

North America has a long history of natural pearling owing in part to its very diverse and rich freshwater mussel resources. After the Civil War pearl jewelry gained greater popularity in the United ...

Gem-quality synthetic or laboratory-grown diamonds are more available in today’s jewelry marketplace than ever before, causing both interest and concern about lab-grown diamonds and whether ...

In November 2022, a parcel of 24 approximately 0.5–1.2 ct spinel crystals, described as cobalt-diffused, were obtained directly from a treater by the research team at GIA in Bangkok. Of these, seven ...

Two specimens of faceted crystalized carbon - both are crystal clear and give off a kaleidoscope of spectral colors in direct light. They appear to be identical. One, however, is a billion or more ...